The present invention relates to the cadastre system and, in particular, it concerns evaluation of measured survey data points against one or more cadastral regulations.
The cadastre system is the system in virtually every country which is used for real estate registration of title, most directly expressed as land boundaries. With regard to the geodetic process of describing real estate locations in a given region, the cadastre system plays both a legal and a technical role. In this specification and in the claims which follow, the terms “cadastral regulation” refers to any set of regulations which make up what is typically referred to as a surveyor ordinance or regulation, as applied in countries, provinces, and other regions responsible for regulating land and land titles.
Cadastral regulations are applied in the supervision of surveying and mapping processes of cadastral objects in respective countries throughout the world. The task of measuring a cadastral parcel is typically performed by licensed surveyors and those operating in accordance with cadastral regulations. Typically, a survey agency or similar governmentally-empowered body is responsible for defining and updating cadastral regulations and for granting licenses to requests by requestors (typically licensed surveyors).
During especially the last decade, governmental survey agencies have been forced to update cadastral regulations at a high frequency. Three main factors are responsible for survey agencies to update cadastral regulations:                the ongoing need to update/upgrade cadastral system processes;        the overall development of new surveying technology; and        the wide and rapid adaptation of new surveying instruments.        
New survey instruments usually suggest new measurement methods, which are cheaper, faster, and more accurate than methods previously used. Most licensed surveyors tend to use new instruments shortly after the instruments are commercially available at reasonable prices. An example of some modern instruments is in the field of Global Positioning Satellite GPS, as applied to surveying, especially Real Time Kinematics GPS (RTK GPS), which is still under examination in many countries. Belle and Wahl, in an article entitled “Cadastral Survey Accuracy Standards”, in Surveying and Land information Science, Vol 63, No. 2, 2003 (pp. 87-106), whose disclosure is incorporated herein by reference, provide an excellent and timely overview of the subject of historical and contemporary methods and constraints related to cadastral surveying, as well as recommendations for specific contemporary standards for cadastral applications employing recent advances in GPS instruments and technology. Two other articles of the exemplary application of GPS technology, whose disclosures are incorporated herein by reference, is “Preliminary Draft Guidelines for Geospatial Positioning Using GPS”, Draft 7, Jun. 10, 2001, Joe Evjen, National Geodetic Survey http://www.ngs.noaa.gov/PROJECTS/GPSmanual/GPSguide.pdf and “Section 12—GPS Surveying, Survey Practice Handbook”, Surveyors Board of Victoria, Dept of Land Information, State of Victoria, Australia http://www.land.vic.gov.au/web/root/domino/cm_da/lcn1c2.nsf/frameset/surveying.
A governmental survey agency must therefore evaluate new instruments to guide surveyors as to the most accurate and reliable ways of using the new instruments. In a similar manner, a survey agency can decide on newer technological standards for measuring. An example for updating a control network could be understood when a survey agency may decide to make Permanent GPS Stations (PGS) the basis of a national control network using Virtual Reference Station (VRS) technology.
The modern cadastral system describes every cadastral object, such as a cadastral parcel, by a set of points. The modern cadastral system, called the Legal Cadastre System (LDC) uses the coordinate values of a point in the national grid system for describing a cadastral parcel. The term “Legal” in LDC is used because of the fact that in a court of law coordinate values of cadastral points are the main evidence of a valid boundary location. As such, surveyors performing measurements in the field, as well as surveyor agencies and regulators responsible for licensing and formally endorsing such field measurement data, must be as careful as possible in reviewing measurement data against cadastral regulations. Essentially, all measurement data, most especially all measured data points, must be completely checked before submittal for licensing and again completely checked by the survey agency to grant a license.
In the past, the number of field points surveyed and the coordinate data obtained from measuring these points was limited, due to technological limitations and also due to the cadastral regulations then in effect. However, today, the number of measurement points and the resultant coordinate data has increased by a number of orders of magnitude. The sharp increase in the number of data points, yielding vastly larger data sets, coupled with the accelerated increase in cadastral regulations represent a new and daunting challenge to both licensed surveyors and to surveyor agencies, and the effort in reviewing and evaluating data sets against cadastral regulations has increased significantly.
When working in the field, the objective of licensed surveyors is to measure a sufficient quality and quantity of points to satisfy requirement of appropriate cadastral regulations. Naturally; a surveyor attempts to work as efficiently as possible and to limit the energy and time expended in the field. Days or weeks after measurements have been made in the field, should a cadastral regulation review and/or analysis of a measured data set yield unacceptable results, the surveyor may have no choice, however, but to return to the field to either augment his data set or to develop a new data set. Certainly a way or device to rapidly evaluate a measurement data set in the field against cadastral regulations could have high value to avoid additional field measurement sessions when, for example, only an additional 30 minutes of measurements were lacking from a data set to allow successful fulfillment of cadastral regulations. At the same time, such a tool could contribute to time and work savings by avoiding the superfluous additional field measurements “just to be sure”.
Additionally, in many locales, when a licensed surveyor submits a set of data as part of a request for a license of a given cadastral parcel, he may be proscribed by law from specifying the cadastral regulation or regulations against which the survey was performed and against which the data set was developed. Because of this situation, the survey agency must typically check a submitted data set against all applicable cadastral regulations—and not against the specific regulation or regulations intended by the licensed surveyor—before the survey agency can give a final response as to which specific regulation or regulations the request and data set successfully fulfill.
All of these factors have contributed to heavier work loads and to a significant increase in response times from survey agencies in granting licensing requests and/or reports.
As a result, there is a need for improved methods and tools in evaluation of measured survey data points against one or more cadastral regulations to allow rapid evaluation of data points sets against cadastral regulations, either in the field or at the desktop.